I've been reading a lot of the threads but I wanted to be sure.... instead of following the standard AHS instructions for mini-mashing that came with this kit... which are basically steeping the grains in a bag... could I just use the 48QT Mash Tun I've built and do a batch sparge on the grains, boil 45 mins, add extract and boil for 15 more minutes?

My grain bill is 4lbs.. I was thinking 7-8 qts of water at 155 for an hour and then sparge with enough water to get me to roughly 6.5 gallons and then start boiling.

The thing I would worry about is not having enough grain to act as a filter. The grain bes itself will filter out a lot of particles. With such a small amout of grain is a big mash tun you might get some grain particles in the wort.

I've been reading a lot of the threads but I wanted to be sure.... instead of following the standard AHS instructions for mini-mashing that came with this kit... which are basically steeping the grains in a bag... could I just use the 48QT Mash Tun I've built and do a batch sparge on the grains, boil 45 mins, add extract and boil for 15 more minutes?

My grain bill is 4lbs.. I was thinking 7-8 qts of water at 155 for an hour and then sparge with enough water to get me to roughly 6.5 gallons and then start boiling.

Am I screwing up?

You can certainly use a mash tun, but keep in mind that the AHS kits contain only about 3 lbs of grain, give or take. By adding all of the extract late and doing a full boil you'll end up with a very dilute wort, resulting in much higher hops optimization than the recipe was formulated for, which may unbalance your beer. So you'll want to do some calculations and reduce the bittering addition by an appropriate amount.